Excrement detection is one of main detection items to detect a patient's conditions. Generally, before formed elements of excrement are detected, some operations such as dilution, filtration and sampling should be performed using an apparatus of preparing excrement detection solutions so as to obtain suspensions for formed element detection. Specifically, firstly excrement specimens are collected and placed in a dilution and filtration device which is a part of an apparatus of preparing excrement detection solutions, and then the dilution and filtration device receiving the excrement specimens is mounted to a stirring and sampling device which is the other part of the apparatus of preparing excrement detection solutions. Afterwards, the excrement specimens are diluted, stirred, filtrated and sampled to obtain specimens to be detected in a detection device.